KR20190122495A - Method for take out the ceramic single crystal ingot - Google Patents

Abstract

The present invention relates to a method for taking out a ceramic single crystal ingot. The method is a method for separating a transparent ceramic physically confined in a crucible from the crucible and comprises the steps of: irradiating an electromagnetic beam to at least a portion of an interface between the crucible and the ceramic in contact with each other; and locally modifying an interface to which the electromagnetic beam is irradiated.

Description

Method for take out the ceramic single crystal ingot}

The present invention relates to a method of easily taking out a ceramic single crystal ingot from a crucible.

The ceramic single crystal ingot is obtained by a manufacturing process of growing from seed crystal to single crystal ingot, and the shape, size, etc. of the seed crystal are limited and used according to the crystal growth method. The ceramic single crystal ingot melts a high melting point ceramic raw material powder and crystallizes and grows a liquid melt from a seed crystal placed in a container having a predetermined shape, that is, a crucible, thereby producing a single crystal ingot.

The production of such ceramic single crystal ingot is carried out in a container having a certain shape, that is, a crucible, in which a high melting point ceramic raw material powder is melted and grown from seed crystal to single crystal.

Before the growth process, seed crystals should be prepared with a predetermined shape, size and crystal orientation determined in advance. Such single crystal seed crystals are most easily cut and used in bulk ingots with ceramic single crystal ingots already made. In order to install the seed crystals in the upper and lower portions of the growth crucible, there is a problem in that cutting and grinding processing are required to an appropriate shape or size. In addition, the seed crystals prepared beforehand should be placed in the crucible so that the contact with the molten liquid can be maintained.

In the case of manufacturing such a single crystal ingot, the shape of the crucible is generally inclined so that the upper part is wide and the lower part is narrow in order to easily take out the ingot, and is mainly made of a high melting point metal such as molybdenum (Mo). In general, the crucible of a metal material has a larger coefficient of thermal expansion than a single crystal ceramic ingot grown largely as a crystal, and thus, the volume reduction of the crucible upon cooling after crystal growth is completed is greater than that of a single crystal ceramic ingot. Due to the difference in volume reduction due to the difference in thermal expansion coefficient, there is a problem that the ingot is constrained to the crucible and cannot be taken out. The ceramic single crystal ingot, which is constrained in this way, must be broken out of the metal crucible in order to pull out the single crystal ingot.In the process of peeling the metal crucible, the ceramic single crystal ingot cracks due to impact during the crucible breakage process, so that the ceramic single crystal ingot cannot be used or is expensive. By using a metal crucible of the one-time problem of manufacturing cost is very high.

Disclosure of Invention The present invention has been made to solve various problems including the above problems, and an object of the present invention is to provide a method for extracting a ceramic single crystal ingot from which the ceramic single crystal ingot can be easily taken out of the crucible so that the one-time crucible can be used continuously two or more times. It is done. However, these problems are exemplary, and the scope of the present invention is not limited thereby.

The method for extracting a ceramic single crystal ingot according to an aspect of the present invention is a method of separating a transparent ceramic, which is physically confined in a crucible, from the crucible, wherein at least a part of an interface between the crucible and the ceramic in the crucible is in contact with each other. Irradiating the electromagnetic beam to the: and locally modifying the interface irradiated with the electromagnetic beam; may include.

In the method of extracting the ceramic single crystal ingot, irradiating the electromagnetic beam may include transmitting the ceramic through the ceramic.

In the method of extracting the ceramic single crystal ingot, locally modifying the interface may include locally melting at least one of the crucible and the ceramic at the interface.

In the method of extracting the ceramic single crystal ingot, the irradiating of the electromagnetic beam may include: a first irradiating step of irradiating an electromagnetic beam on an upper surface of the ceramic in contact with the crucible on an upper surface of the ceramic in the crucible; And a second irradiation step of irradiating an electromagnetic beam through the ceramic transparent to the side interface where the ceramic contacts the crucible on the side surface of the ceramic in the crucible.

In the extraction method of the ceramic single crystal ingot, the third irradiation step of irradiating an electromagnetic beam by transmitting the transparent ceramic to the lower interface of the ceramic in contact with the crucible at the lower surface of the ceramic in the crucible; have.

In the method of extracting the ceramic single crystal ingot, the ceramic single crystal ingot having the first thickness is separated by irradiating an electromagnetic beam through the transparent ceramic at a point having a first thickness on the upper surface of the ceramic in the crucible. Irradiation step; may further include.

In the method of extracting the ceramic single crystal ingot, in the first irradiation step, each of the electromagnetic beams may be irradiated with a predetermined region of the upper interface between the ceramic and the crucible by using a plurality of electromagnetic beams.

In the method of extracting the ceramic single crystal ingot, in the first irradiation step, the electromagnetic beam may irradiate a predetermined region of the interface between the ceramic and the crucible with a linear light source.

In the method of extracting the ceramic single crystal ingot, before the first irradiation step, an interface measurement step of measuring the interface of the ceramic in contact with the crucible inside the crucible; may further include.

According to one embodiment of the present invention made as described above, it is possible to take out the ingot so as not to damage the ingot by using an electromagnetic beam of the single crystal ingot confined to the crucible, the expensive metal crucible by taking out without breaking the crucible Can be used continuously can have the effect of reducing the production cost.

In addition, the ceramic single crystal ingot is cut and separated, leaving only the seed crystal shape, and left in the ceramic single crystal seed crystal crucible, when manufacturing the next ceramic single crystal ingot, the manufacturing process required for shape processing or seed orientation determination is shortened, thereby reducing manufacturing cost. A method for taking out a single crystal ingot can be provided. Of course, the scope of the present invention is not limited by these effects.

1 is a perspective view showing a first irradiation step of the extraction method of the ceramic single crystal ingot according to an embodiment of the present invention.
2 is a perspective view showing a second irradiation step of the method for extracting the ceramic single crystal ingot according to the embodiment of the present invention.
3 is a perspective view showing a third irradiation step of the extraction method of the ceramic single crystal ingot according to another embodiment of the present invention.
4 is a perspective view showing a fourth irradiation step of the extraction method of the ceramic single crystal ingot according to another embodiment of the present invention.
5 is a perspective view illustrating a crucible in which a ceramic single crystal ingot is taken out and a seed crystal remains according to another embodiment of the present invention.
6 is a perspective view illustrating a method of extracting a ceramic single crystal ingot according to still another embodiment of the present invention.

Hereinafter, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, and the following examples can be modified in various other forms, and the scope of the present invention is It is not limited to an Example. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of description.

First, the method of extracting the ceramic single crystal may include adding a raw material to the crucible, a heating step, and a growth step. For example, a raw material capable of growing a transparent ceramic single crystal such as sapphire, spinel, garnet, yag, or the like may be added.

Crucibles can be used as materials such as refractory metals (Mo, W, Ta, Nb) when growing transparent ceramic single crystals such as sapphire, spinel, garnet, yag, etc. It may have durability.

For example, the raw material is alumina as a single crystal raw material, the crucible is a crystal growth process using molybdenum (Molybdenum) refractory metal, the alumina raw material is heated to a high temperature to melt and cool the seed crystals appropriately In this case single crystal sapphire ingots can be prepared when crystallization starts and growth occurs in the seed crystals.

After the step of injecting the raw material, it may further comprise a heating step. The heating step is a step of heating the crucible, the raw material can be heated to a high temperature to make the molten state.

For example, when a heating coil is formed around the crucible and the raw material is put into the crucible, the heating coil may heat the crucible to melt the raw material therein.

After the heating step, it may further comprise a growth step. The growth step is a step in which the raw material grows inside the crucible, and the cooling step is a step in which the raw material is formed into an ingot by cooling the crucible.

The growth step may be seed crystals when the raw material is grown, and when the seed crystals are properly cooled in the cooling step, when the crystallization starts and growth occurs in the seed crystals, an ingot, for example, a single crystal sapphire ingot may be manufactured. have.

The crucible may have a smaller cross section at the bottom than a cross section at the top to facilitate separation of the ceramic.

The sapphire single crystal ingot is enclosed in the molybdenum crucible when the crystal growth process from the seed crystal is completed in the molybdenum crucible container. In this case, crystal growth may be terminated in a state in which the ceramic single crystal ingot is constrained by the deformation of the molybdenum crucible or the difference in thermal expansion coefficient.

For example, the molybdenum crucible may be a metal material having a higher coefficient of thermal expansion relative to the ceramic single crystal ingot, and thus, the molybdenum crucible may have a larger volume change due to temperature change than the ceramic single crystal ingot.

That is, the ceramic single crystal ingot, in which the crystal growth process is completed from the seed crystal through heating and cooling, may be firmly bound to the molybdenum crucible having a relatively large volume change according to temperature change in the molybdenum crucible.

An electromagnetic beam may be used to extract the ceramic single crystal ingot from the molybdenum crucible.

As an example, a method of separating the molybdenum crucible from the ceramic single crystal ingot using an electromagnetic beam may include irradiating an electromagnetic beam to at least a portion of an interface between the molybdenum crucible and the ceramic single crystal ingot inside the molybdenum crucible. And locally modifying the interface to which the electromagnetic beam is irradiated.

In some cases, irradiating the electromagnetic beam may pass through the ceramic and directly irradiate the interface. That is, the ceramic constrained inside the crucible is optically transparent to allow transmission of the electromagnetic beam, and thus the electromagnetic beam may pass through the transparent ceramic and irradiate the interface. An example of an electromagnetic beam passing through the transparent ceramic may include a laser, but is not limited thereto.

In the vicinity of the light converging point irradiating the electromagnetic beam, physical properties of the interface between the ceramic and the crucible may be locally changed by multiphoton absorption or a corresponding nonlinear absorption effect, thereby forming a modified region. For example, near the condensing point, the energy of the laser L is absorbed by the bonding surface where the ceramic and the crucible are in contact, and instantaneous melting occurs, and the ceramic and / or crucible may be locally melted at the interface between the ceramic and the crucible. . Local melting at this interface can separate the ceramic and the crucible. Alternatively, separation may occur as the local melting region solidifies rapidly after the irradiation of the electromagnetic beam is stopped.

When separation occurs locally at the interface between the crucible and the ceramic ingot, these separated regions propagate to other interface regions of the crucible and the ceramic ingot so that the separated regions can be expanded and separated and taken out as a whole. Irradiation of the electromagnetic beam for separation at the interface between the crucible and the ceramic ingot can be performed once or multiple times while changing the position of the interface.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 6 are perspective views showing each step of the extraction method of the ceramic single crystal ingot according to an embodiment of the present invention.

First, a method of extracting a ceramic single crystal ingot according to an embodiment of the present invention is a method of separating the transparent ceramic 10, which is physically confined in the crucible 20, from the crucible 20, and in the crucible 20. Irradiating the electromagnetic beam 30 to at least a portion of the interface where the crucible 20 and the ceramic 10 are in contact with each other, and locally modifying the interface to which the electromagnetic beam 30 is irradiated.

Irradiating the electromagnetic beam may include a first irradiation step and a second irradiation step.

As shown in FIG. 1, the first irradiation step is a method of separating the transparent ceramic 10, which is physically confined in the crucible 20, from the crucible 20, and the first irradiation step is a crucible 20. ) Irradiating the electromagnetic beam 30 to the upper interface C1 where the ceramic 10 contacts the crucible 20 at the upper surface of the ceramic 10.

The first irradiation step is a step of irradiating the electromagnetic beam 30 to the contact surface of the ceramic 10 and the crucible 20 in order to separate the ceramic 10 and the crucible 20 in the crucible 20 in which ingot formation is completed. to be.

As shown in FIG. 1, the first irradiation step is a step of irradiating a laser (L) to the upper interface (C1) in contact with the ceramic 10 and the crucible 20 on the upper surface of the ceramic 10. The laser L is irradiated from the surface of the ceramic 10 to facilitate separation of the ceramic 10 and the crucible 20.

As shown in FIG. 2, the second irradiating step is transparent to the side interface C2 where the ceramic 10 contacts the crucible 20 at the side surface of the ceramic 10 in the crucible 20. It is a step of irradiating the electromagnetic beam 30 by passing through.

In the second irradiation step, after the laser L is irradiated and separated from the upper interface C1 of the ceramic 10, the laser L penetrates the transparent ceramic 10 so that the ceramic 10 and the crucible 20 are separated. It is a step irradiated to the side interface C2 which is an inner wall surface of the crucible 20 which is in contact.

In the first irradiation step, the laser (L) is irradiated to the upper interface (C1) of the surface of the ceramic 10, in the second irradiation step, the laser (L) is transmitted through the ceramic 10 to the side interface (C2) By irradiating to the wavelength of the laser (L) irradiated in the first irradiation step and the laser (L) irradiated in the second irradiation step can control the wavelength to separate the ceramic 10 and the crucible 20 can be taken out. .

In the second irradiation step, the ceramic 10 may be transparently formed in the visible light region so that the laser L may pass through the ceramic 10 to be irradiated to the side interface C2.

This second irradiation step may be performed once or a plurality of times by changing the position of the side interface.

Locally modifying the interface may include locally melting at least one of the crucible and the ceramic at the interface.

3 is a perspective view showing a third irradiation step of the extraction method of the ceramic single crystal ingot according to another embodiment of the present invention.

The extraction method of the ceramic single crystal ingot according to another embodiment of the present invention may include a third irradiation step.

In the third irradiation step, the electromagnetic beam 30 is transmitted through the transparent ceramic 10 through the lower interface C3 in which the ceramic 10 contacts the crucible 20 on the lower surface of the ceramic 10 in the crucible 20. Step to investigate.

For example, as shown in FIG. 3, in the third irradiation step, the laser L is irradiated from the upper interface C1 of the ceramic 10 in the first irradiation step, and in the second irradiation step, the laser ( L is transmitted through the transparent ceramic 10 and irradiated to the side interface C2 where the ceramic 10 and the crucible 20 are in contact with each other, and then the lower portion of the ceramic 10 that is in contact with the crucible 20. Laser L is irradiated to interface C3.

As described above, the laser L is absorbed by the lower interface C3 in which the ceramic 10 and the crucible 20 are in contact with each other, and instantaneous melting occurs, and the ceramic 10 and the crucible 20 are separated and taken out while being cooled. Can be.

Through the first irradiation step and the second irradiation step, the ceramic 10 and the crucible 20 may be irradiated to contact all the joint surfaces of the ceramic 10 and the crucible 20 to be separated.

4 is a perspective view showing a fourth irradiation step of the extraction method of the ceramic single crystal ingot according to another embodiment of the present invention.

The fourth irradiating step transmits the transparent ceramic 10 to the point having the first thickness d on the upper surface of the ceramic 10 in the crucible 20 and irradiates the electromagnetic beam 30 with the first thickness d. The step of separating the ceramic single crystal ingot having a).

For example, as shown in FIG. 4, in the first irradiation step, the laser L is irradiated from the upper interface C1 of the ceramic 10, and in the second irradiation step, the laser L is transparent. After irradiating to the side interface (C2) where the ceramic 10 and the crucible 20 are in contact with each other, the ingot is irradiated by irradiating a laser (L) below the first thickness (d) from the surface of the ceramic (10). By separating, the ceramic single crystal ingot 10-1 can be cut and separated.

In the fourth irradiation step, the ceramic single crystal ingot 10-1 is separated by irradiating the electromagnetic beam 30 through the transparent ceramic 10 at a point having a first thickness d on the upper surface of the ceramic 10. When a laser having a high unit energy is irradiated at a predetermined focal length through a transparent ceramic single crystal surface, the sapphire single crystal ingot 10-1 and the single crystal seed crystal 10-2 are separated by thermal energy generation at the irradiated focal region. Seed crystals may be prepared, for example, the ceramic 10 and the crucible 20 may be separated and extracted as shown in FIG. 5.

 In this case, the laser beam may further include an electromagnetic beam moving device capable of moving the electromagnetic beam in order to constantly irradiate the focal length of the laser. The high energy beam is directly irradiated onto the ceramic single crystal ingot and left in the crucible to manufacture the next ceramic single crystal ingot. In this case, the manufacturing process required for shape processing, seed orientation determination, etc. may be shortened, thereby reducing the manufacturing cost.

As another embodiment of the present invention, the interface measuring step (S50) for measuring the interface of the ceramic 10 in contact with the crucible 20 in the crucible 20 before the first irradiation step may be further included.

For example, when an ingot is formed in the crucible by inputting and melting a raw material into the crucible, the surface of the ingot and the interface between the crucible and the ingot can be measured. In this case, the ingot may be ceramic.

The first irradiation step through the information measured by measuring the surface of the ceramic 10 and the upper interface (C1), the side interface (C2), the lower interface (C3), which is the bonding surface of the crucible 20 and the ceramic 10, or In the second irradiation step, the laser beam L may be irradiated using the electromagnetic beam 30.

The ceramic 10 can be taken out from the crucible 20 so that the ceramic 10 can not be damaged through the measured information by measuring the interface, and it can be taken out without damaging the crucible and the expensive metal crucible can be continuously used. It can have the effect of reducing the cost.

In still another embodiment of the present invention, in the first irradiation step, each of the electromagnetic beams 30 using the plurality of electromagnetic beams 30 is in contact with the ceramic 10 and the crucible 20 at the upper interface C1. The predetermined area can be examined.

For example, as shown in FIG. 6, the two electromagnetic beams 31 and 32 each shorten the separation time by irradiating the upper interface C1 to each of the electromagnetic beams 31 and 32 simultaneously. Can be.

When the electromagnetic beam 30 is irradiated to the upper interface C1 of the ceramic 10 and the crucible 20, the first electromagnetic beam 31 is one side of the upper interface C1 of the crucible 20 that is input in advance. The second electromagnetic beam 32 may irradiate the other side of the upper interface C1 of the crucible 20 that is input in advance. In this case, the plurality of electromagnetic beams 31 and 32 may irradiate a laser L or a linear light source to the upper interface C1 of the ceramic 10 and the crucible 20.

In the method of extracting the ceramic single crystal ingot according to another embodiment of the present invention, the electromagnetic beam 30 may irradiate a predetermined region of the interface between the ceramic 10 and the crucible 20 with a linear light source in the first irradiation step. .

By irradiating the linear light source to the interface between the ceramic and the crucible, separation of the interface formed on the ceramic and the crucible can be facilitated at a faster time.

The linear light source may be irradiated with a linear light source by aligning a plurality of electromagnetic beams, and may further include a device for forming a lens, a prism, or the like on the electromagnetic beam irradiated with a laser, and converting the light into a linear light source. have.

Although not shown, it may include a condenser lens for collecting the laser to the target portion and a rotating unit for irradiating the laser in the target direction.

Although the present invention has been described with reference to the embodiments shown in the drawings, these are merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

10: ceramic
20: crucible
30: electromagnetic beam
L: laser
C1: upper interface
C2: side interface
C3: lower interface

Claims (9)

As a method of spaced apart from the crucible transparent ceramic physically confined within the crucible,
Irradiating an electromagnetic beam to at least a portion of an interface where the crucible and the ceramic contact each other inside the crucible: and
Locally modifying the interface to which the electromagnetic beam is irradiated;
Including, the extraction method of the ceramic single crystal ingot. The method of claim 1,
Irradiating the electromagnetic beam,
The ceramic single crystal ingot extraction method comprising the step of irradiating through the ceramic. The method of claim 1,
Locally modifying the interface,
And locally melting at least one of the crucible and the ceramic at the interface. The method of claim 1,
Irradiating the electromagnetic beam,
A first irradiation step of irradiating an electromagnetic beam to an upper interface of the ceramic in contact with the crucible on an upper surface of the ceramic in the crucible; And
A second irradiation step of irradiating an electromagnetic beam through the ceramic transparent to a side interface where the ceramic contacts the crucible at a side surface of the ceramic in the crucible;
Including, the extraction method of the ceramic single crystal ingot. The method of claim 4, wherein
A third irradiation step of irradiating an electromagnetic beam through the ceramic transparent to a lower interface in which the ceramic contacts the crucible on a lower surface of the ceramic in the crucible;
Further comprising, the extraction method of the ceramic single crystal ingot. The method of claim 4, wherein
A fourth irradiation step of separating the ceramic single crystal ingot having the first thickness by transmitting an electromagnetic beam through the ceramic transparent to a point having a first thickness on the upper surface of the ceramic in the crucible;
Further comprising, the extraction method of the ceramic single crystal ingot. The method of claim 4, wherein
In the first irradiation step,
And a plurality of electromagnetic beams each irradiates a predetermined region of the upper interface where the ceramic and the crucible are in contact with each other. The method of claim 4, wherein
In the first irradiation step,
And the electromagnetic beam irradiates a predetermined region of an interface between the ceramic and the crucible with a linear light source. The method of claim 4, wherein
Prior to the first irradiation step,
An interface measuring step of measuring an interface of the ceramic in contact with the crucible inside the crucible;
Further comprising, the extraction method of the ceramic single crystal ingot.

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